PD-L1 Inhibitor Combined With Apatinib as First-line Maintenance Treatment for Extensive-stage Small Cell Lung Cancer

Every 3 weeks (21 days) is a treatment cycle. After 4-6 cycles of induction therapy, patients whose efficacy is evaluated as CR, PR or SD (according to RECIST 1.1) will enter maintenance therapy until the disease progresses and becomes intolerable. Toxic and side effects, death, withdrawal of information or the investigator's decision to withdraw the subject from the study, non-compliance with study treatment or other reasons specified in the study procedures or protocol, or treatment for up to 2 years. Maintenance treatment: PD-L1 inhibitor + apatinib 250 mg po qd, maintained for up to 2 years. Note: The specific PD-L1 inhibitor is selected by the researcher, such as adebelimab 1200mg iv, q3w; or atezolizumab 1200mg iv d1, q3w; or durvalumab 1500mg iv d1, q3w . The selection of PD-L1 inhibitors in the maintenance phase is consistent with the first-line standard treatment in the induction phase.